Duplicated circuit arrangement for fast transmission and repairability

Abstract

Duplicated circuit arrangement comprising a main processor (30) and its P bit data bus (44), and two identical redundant devices (21:22), each device is comprised of a processing element (23;35) performing the same task in parallel on a P bits word, and send/receive circuits (24,25;36,37) controlled by the main processor through lines (SR11 to SR22) to transmit said word to and from said main processor. For each device, the send/receive circuits are split into two parts. Send/receive circuit of the first device (21) is split in two parts (24, 25); the first part (24) handles the P/2 Most Significant Bits (MSB's) and the second part (25) handles the P/2 Less Significant Bits (LSB's). In normal operation, during the transmission step, only the first part (24) is allowed to send bits on one half (33) of the data bus (44). Symmetrically send/receive circuit of the second device (22), is also split in two parts (36, 37); the first section (36) handles the P/2 Most Significant bits (MSB's) and the second part (37) handles the P/2 Less Significant Bits Z(LSB's); only the second part (37) is allowed to send bits on the other half (34) of the data bus (44). Therefore, the data bus driving effort is equally shared between the two devices, the maximum number of simultaneous switching is P/2 for each device. This reduction allows greater transmission speed on large busses.